The present invention relates to a tank cap with a lock which is attached to a fuel supply port of a fuel tank. In addition, the present invention also relates to a method of packing the tank cap with a lock.
Conventionally, a tank cap with a lock, which can be removed from a fuel supply port only when it is unlocked by a predetermined key, is used for the fuel supply port of a fuel tank of a motorcycle. This tank cap with a lock is disclosed, for example, in Japanese Examined Patent Publication No. 58-48423. This tank cap with a lock is arranged with the intention of preventing the key from withdrawing from the key hole of the tank cap in a state that the tank cap is being removed from the fuel tank.
When the tank cap is attached to the fuel supply port, a gasket member is brought into close contact with the peripheral edge portion of the fuel supply port and simultaneously a locking piece of the tank cap with a lock automatically protrudes in the transverse direction by the action of a spring incorporated into the tank cap with a lock. Then the locking piece of the tank cap with a lock is locked with the peripheral edge portion of the fuel supply port, so that the tank cap is put into a locked condition. In this locked condition, the key can be withdrawn from the key hole.
Unless the tank cap is unlocked by the key, it is impossible to remove the tank cap with a lock from the fuel supply port. In order to remove the tank cap with a lock from the fuel supply port, it is necessary that the key is inserted into the key hole of the tank cap and turned. Due to this operation, the locking piece can be unlocked from the peripheral edge portion of the fuel supply port. In this way, the tank cap with a lock can be removed from the fuel tank.
The above-mentioned conventional tank cap with a lock is designed, in such a manner that it is impossible to withdraw the key from the key hole in the removed state in which the tank cap with a lock is being removed from the fuel tank. Namely, in the conventional tank cap with a lock, the tank cap is made with the intention of preventing the key from withdrawing from the tank cap when the tank cap is being removed from the fuel tank.
However, according to the arrangement of the above tank cap, there is a possibility that the key can be withdrawn from the key hole in a state that the tank cap is being removed from the fuel tank as follows. In the case where a gasket member is pushed up by a hand while the tank cap with a lock is being removed from the fuel tank, an elevating cylinder of the tank cap with a lock is raised in cooperation with the movement of the gasket member, and then the locking piece is unlocked from the stopper surface of the elevating cylinder and protrudes outside. Therefore, the key can be withdrawn from the tank cap.
As described above, in the conventional example of the tank cap with a lock, when the gasket member is pushed up somehow, the key is withdrawn from the tank cap, so that there is a possibility that the key thus withdrawn is lost.